1. Field of the Invention
The present invention relates to a curable polymer composition. More particularly, the present invention relates to a curable polymer composition comprising a specific alkyl acrylate and/or alkyl methacrylate (hereinafter collectively referred to as "alkyl (meth)acrylate") base copolymer and an oxyalkylene base polymer having at least one silicon-containing group to the silicon atom of which at least one hydroxyl group or hydrolyzable group is bonded and which is cross linkable through formation of a siloxane bond (hereinafter referred to as "silicon-containing reactive group").
2. Description of the Related Art
The oxyalkylene base polymer having at least one silicon-containing reactive group (hereinafter referred to as "oxyalkylene base polymer (B)" or "polymer (B)") is known from U.S. Pat. Nos. 3,971,751, 3,979,384 and 4,323,488, Japanese Patent Publication Nos. 36319/1970, 12154/1971 and 32673/1974 and Japanese Patent Kokai Publication Nos. 156599/1975, 73561/1976, 6096/1979, 82123/1980, 123620/1980, 125121/1980, 131022/1980, 135135/1980 and 137129/1980.
The oxyalkylene base polymer (B) can be cured even at room temperature to give a cured material with good tensile properties so that it can be used as a sealant. The oxyalkylene base polymer (B) has such advantage that various coatings can be formed on a surface of its cured material, although the polymer (B) has drawbacks such that some acrylic coatings have poor adhesive properties to the surface of the cured material of the polymer (B), or almost all alkyd resin coatings cannot be hardened or dried on the surface of the cured material of the polymer (B). In addition, the cured material of the polymer (B) has insufficient weather resistance.
Several measures to improve such drawbacks of the oxyalkylene base polymer (B) have been proposed.
For example, it is proposed to blend a (meth)acrylate base polymer having the silicon-containing reactive group in the oxyalkylene base polymer (B) (cf. U.S. Pat. No. 4,593,068 and Japanese Patent Kokai Publication Nos. 122541/1984 and 31556/1985). Although the blending of such (meth)acrylate base polymer improves the drawbacks such as insufficient weather resistivity of the cured material of the oxyalkylene base polymer (B) and difficult coating with the acrylic or alkid resin coating, it is difficult to prepare a transparent composition or a composition with good storage stability which is one of the practically important properties of the curable polymer composition.
Alternatively, it is proposed to modify the oxyalkylene base polymer (B) through polymerization of a (meth)acrylate monomer in the presence of the polymer (B) (cf. U.S. Pat. No. 4,687,818 and Japanese Patent Kokai Publication Nos. 78223/1984, 168014/ 1984, 228516/1985 and 22817/1985). Although this method can improve the storage stability of the curable polymer composition, producibility, particularly per unit volume of a polymerization reactor is decreased since the once produced polymer (B) is recharged in the reactor and then the (meth)acrylate monomer is polymerized. Further, when polymers having a different composition of the oxyalkylene base polymer and the (meth)acrylate monomer are to be produced, the (meth)acrylate monomer should be polymerized in the presence of the oxyalkylene base polymer (B) in different batches. Therefore, the overall procedures are very troublesome.
Accordingly, it has been desired to provide a curable polymer composition having a suitable composition by simple blending.